Research on intelligent cutting control technology of transverse moving machine for large cross-section roadheader

With the continuous development of the coal mine industry in our country, the cross-section of the roadway is getting larger and larger. The widely used EBZ series roadheader cannot complete the roadway cutting operation with a large cross-section at one time, so it usually needs to move the equipment left and right to complete all its cutting tasks. This paper studies the intelligent control technology of large cross-section roadway cutting, which mainly solves the positioning and attitude determination technology of roadheader in the large cross-section, and offers an accurate shape-cutting control technology and a path planning technology using a lateral moving machine. This paper proposes to combine the signals of laser sensor and fiber-optic inertial navigation system to form a combined positioning and attitude determination system, so as to make use of the advantages and avoid the disadvantages of their respective systems, and improve the accuracy of roadheader positioning and attitude determination. A swing kinematics model of the cutting arm is established, based on which the precise motion control of the first roadway section cutting and the second roadway section cutting can be realized. A key parameter calculation model of roadheader lateral moving machine is put forward to calculate the operation parameters for roadheader lateral moving machine path planning. Finally, the experimental research on intelligent cutting control technology of large cross-section roadheader is carried out in 12307 intelligent heading face of Wangjialing Coal Mine. The results show that the positioning error of the combined positioning and attitude determination system proposed in this paper is between 50-90 mm in the X-axis direction and between 25-45 mm in the Y-axis direction. The average attitude measurement error of heading angle is between 0.5 and 1.5°. This makes the technology appropriate for engineering use. The studied cutting control system achieves a cutting error of 25-50 mm for the first section, and a cutting error of 40-90 mm for the complete section. The complete section cutting error meets the ±100 mm cutting error requirement required in engineering. The intelligent cutting control technology of the lateral moving machine of the large-section tunnel boring machine studied in this paper can realize accurate cutting of the large-section tunnel of 5.6 meters. The research results of this paper provide a reference for the intelligent construction of heading faces

Research on an improved deadbeat model predictive current control of double three-phase open-winding permanent magnet motor

Model predictive current control has high control accuracy and good control performance, and has been widely applied in the control strategy of dual three-phase permanent magnet synchronous motors. This article proposes an improved deadbeat model predictive current control (DMPCC) method by analyzing the mathematical model of a dual three-phase open-winding permanent magnet synchronous motor. One inverter predicts and calculates the optimal voltage vector through the deadbeat model, while the other inverter calculates the optimal voltage vector through the value function rolling optimization. This method reduces the computational workload of the controller, avoids the delay problem of the traditional model predictive current control (MPCC) method, improves the system's response speed, effectively suppresses the current in the harmonic sub-plane, and reduces torque ripple. The simulation results have verified the accuracy and speed of the above control method

Impact of ambient temperature on the perceived quality consistency of automotive interior and exterior trim components

Currently, automotive manufacturers highly prioritize the perceived quality of vehicles, with dimensional engineering being a key influencing factor. Automotive interior and exterior trim components undergo slight deformation due to temperature changes, affecting fit dimensions and imposing stricter consistency requirements. This paper examines the deformation mechanisms of typical parts under varying temperatures using dimensional engineering techniques to study the impact on component gaps. Testing quantifies changes in gap width and surface flatness during temperature variations, providing a theoretical basis for design. The research offers practical guidance for identifying potential issues early in product development and ensuring effective collaboration in production, helping companies achieve higher standards and superior quality

A study on active structural acoustic control using force radiation modes

Active Structural Acoustic Control (ASAC) is an effective method for sound radiation control. To solve the coupling effect or inconvenience problems existed in the application of conventional methods, by utilizing the characteristic of intuitive representation of radiated sound power through force radiation modes, the control forces are designed to make the total excitation force vector orthogonal to each dominant force radiation mode. Therefore, an ASAC method by utilizing force radiation modes is proposed, and detailed theoretical research and numerical calculation analysis are carried out. The research results indicate that the control force requirement can be intuitively obtained through the force radiation modes, and decoupled control of radiated sound power corresponding to each force radiation mode is achieved by the proposed method. Thus, the control strategy and system construction can be greatly simplified, and structural acoustic radiation can be effectively controlled

Model study on transmission loss of the split-stream rushing exhaust muffler for diesel engine

Numerical simulation was carried out on the transmission loss of the split-stream rushing exhaust muffler, and the accuracy of the simulation method was verified through experiments. Taking the transmission loss as the response value, the experiment was designed by using Box-Behnken module of Design Expert software. A mathematical regression model of transmission loss with experiment factors was established by using the Box-Behnken experimental design scheme, the experiment factors include the diameter of the interior pipe, the shape of the rushing hole, the center distance of the rushing hole, the cone angle of the interior pipe as well as the number of rushing holes, and the mathematical regression model's significance was tested. The response curvatures of second order interaction to the transmission loss by different variables were obtained and the interaction relationships among variables were analyzed. The results showed that the diameter of the interior pipe and the center distance of the rushing hole are the main factors that affect the transmission loss. The transmission loss increases with the increase of the diameter of the interior pipe. When the diameter of the interior pipe is between 70 mm and 80 mm, the transmission loss firstly increases and then decreases with the center distance of the rushing hole changes from Smin to Smax. When the diameter of the interior pipe is between 80 mm and 90 mm, the transmission loss decreases with the center distance of the rushing hole changes from Smin to Smax. The effect of the rushing hole shape on transmission loss is not significant. The transmission loss increases with the increase of the number of rushing holes, but the increase of transmission loss is not significant with the number of rushing holes changes from 4 to 6 groups. Taking the transmission loss as the optimization index, the better experimental condition was obtained. Compared to the not optimized muffler of the sample engine, the average transmission loss of the optimized muffler is increased by 48.70 % when the frequency is 0-1000 Hz, the average insertion loss of the optimized muffler is increased by 7.4 %. At inlet air velocity of 40 m/s, the pressure loss is reduced by 56.8 %

Analysis of changes in lower limb joints of athletes during the movement of wild horses’ mane parting based on biomechanics

In the era of fitness, more and more young people are familiar with Taijiquan, a kind of physical fitness exercise. By conducting biomechanical analyses of the movements of Taijiquan, it is possible to exercise the body better. Numerous techniques in Taijiquan make it difficult to study each individually. Therefore, this paper studied the movement of “wild horses’ mane parting” in terms of biomechanics by analyzing the joint angle, stiffness, and impulse during this movement. Twenty male athletes were selected as subjects and divided into a professional group and a beginner group according to their training periods. High-speed cameras were used to shoot the “wild horses’ mane parting” movement. The angles of lower limb joints in these athletes were measured to calculate joint impulse and stiffness. The results showed that, compared with the professional group, there were significant differences in the adduction and abduction angle and the internal and external rotation angle between the beginner group and the professional group in the single-leg support movement stage (P< 0.05). There were also significant differences in joint impulse and stiffness (P< 0.05). Compared with beginners, long-term professional practitioners can make their movements more standardized. By comparing movements and data analysis, beginners can make their movements more standardized when practicing Taijiquan and avoid the risk of sports injury. The novelty of this article lies in the use of high-speed cameras to capture athletes’ movements, enabling accurate analyses of their joints and providing effective references for precise training

Optimal trajectory control for the yaw system vibration and crawling jitter of a wind turbine

A kinematics model of the yaw system is investigated based on an equilibrium position in yaw motion, aiming at the suppression of the yaw system vibration and crawling jitter (CJ) of a wind turbine. A nonlinear CJ model is constructed and integrated to form the governing equation of the system. An optimal trajectory control (OTC) strategy is investigated to suppress the nonlinear system vibration. This strategy uses a differential evolution algorithm to perform an optimal planning along a given ideal path, thereby achieving a goal of suppressing vibrational amplitude and frequency. A tracking of the optimal trajectory is achieved based on proportional-derivative (PD) control using the differential evolution, to ensure minimal energy consumption throughout the entire tracking process. Currently, there is little literature discussing the CJ phenomenon in detail. The CJ phenomenon is an extreme situation that occurs during yaw motion and has significant destructive power under extreme working conditions. The control planning proposed in this article can completely eliminate the CJ phenomenon and suppress the yaw vibration. The engineering application effect of the proposed control algorithms is demonstrated based on a type of concise OPC technique

Variable damping mechanism and verification of the torsional damper for a parallel-series hybrid electric vehicle

The torsional vibration of hybrid electric vehicles (HEVs) powertrain coupled with multiple power sources is more complex, and the hysteresis torque requirements are different under different working conditions. Therefore, this study investigates the impact of the hysteresis torque value on damping performance for torsional dampers under diverse working conditions through modeling and simulation. A configuration for a torsional damper that enables variable hysteresis torque in different working conditions is proposed. Simulation results demonstrate that the variable hysteresis torsional damper reduces angular acceleration fluctuation amplitude by 54.5% during motor-assisted engine starting and by 20.2 % during combined drive conditions compared to traditional dampers, effectively attenuating vibration under two different working conditions. The proposed variable hysteresis torsional damper configuration is verified to meet design requirements for different working conditions

Dynamics of a wheeled robot driven by an unbalanced rotor and equipped with the overrunning clutches

Vibration-driven locomotion principles are currently of significant interest among designers and researchers dealing with mobile robotics. Among a great variety of robots chasses, the wheeled ones are the most commonly used. The major purpose of this study consists in defining the dynamic characteristics of the wheeled vibration-driven robot equipped with the centrifugal (inertial) vibration exciter (unbalanced rotor) and overrunning clutches ensuring the robot’s wheels rotation in one direction. The research methodology is divided into three basic stages: developing the robot’s dynamic diagram and deriving the motion equations followed by numerical modeling in the Mathematica software; designing the 3D-model and simulating the robot motion in the SolidWorks software; creating the experimental prototype and conducting the full-scale tests. The obtained results show the time dependencies of the robot’s body acceleration, speed, and displacement at certain operational conditions. The main scientific novelty of the paper resides in substantiating the relationships between the robot’s design parameters and its dynamic characteristics under different operational conditions. The performed investigations can be useful for researchers and designers dealing with vibration-driven robots, capsule-type locomotion systems, pipelines inspecting vehicles, etc